It finally happened and I broke my first carbon (fixed length) paddle (my favourite one) yesterday while surfing. I was on a nice wave and it was right as I was getting the last power stroke in. This one has seen a few years use, but I was quite surprised as I never nicked it. I bought it used (was fixed before) and it broke shortly below the mid section where my hand gripped it. The previous fix had a short 15cm carbon rod inserted into the shaft as a joint and it broke right at the end of the insert, which seems to indicate all the stress was at that point where the insert carbon joint stopped and over time must have just gave in.

I will be fixing it, but am thinking of lengthening the carbon insert to spread the stress point lower down the shaft, but I am concerned this will change the flex and may make it too stiff. Any thoughts and experience with similar repairs?
I've already heated the shaft to loosen the epoxy and removed the carbon insert. Luckily it was a clean break so I probably just lost about 1cm where I neatly sanded the shaft edges on both sides.

I also want to get a new paddle so I have two in case one breaks. Any recommendations for a strong paddle that's also light weight?

I've just repaired one and to be honest couldn't tell the difference. The shaft on mine is tapered, I used the part I'd cut off to reduce the length to insert inside the break, epoxy and re join. Sanded the outside, used a light spray adhesive to hold a piece of carbon/glass weave in place, epoxy laminated and wrapped tightly in peelply. The result just left the weave to be filled and sanded. I've heard that a piece of shaft the same size can be cut longitudinally to squeeze it in if the shaft isn't tapered.

Thanks for the feedback everyone.